Gun sight



33-238. cm 2.502.506 SR 7 HEW? April 4, 1950 E. E. CHASE ET AL 2,502,506

GUN SIGHT Original Filed March 27, 1945 6 Sheets-Sheet l lnz/eniorsErnesZE Chase William VGooczhue Ernest TNo/ues April 4, 1950 E. E. CHASEET AL 2,502,506

GUN SIGHT Original Filed March 27, 1945 6 Sheets-Sheet 2 T H R d, ZInventor's ange a m frneszf Chas Component Comporzanz e I 9 CourseI/VzUz'am T/Gooahue A '0 Ernes; l vokes i L251 ant Zhngentigl Fran/z E525 a zzon 4' Line Of Sight Line Or" 51 m April 1950 E. E. CHASE ET AL2,502,506

GUN SIGHT Original Filed March 27, 1945 6 SheetsSheet 3 lm/emors ErnestEChczse l/Vzliz'am VGoodhue Ernesz dNokes Frank E. Szr'azzonzh'eir'Azzorney April 4, 1950 E. E. CHASE ET AL GUN SIGHT 6 Sheets-Sheet4 Original Filed March 27, 1945 lnveniors Erneszf. Chase Fran/cEGZrazfon April 4, 1950 E. E. CHASE ET AL 2,502,506

GUN SIGHT Original Filed March 27, 1945 6 Sheets-Sheet 5 nveniarsErnesZEChaSe LVN/2am T/Goodhue fr-nesz G. Nokes' gr'czrzlr ESzr-azzoniSEfiRCH ROE? April 4, 1950 E. E. CHASE ET AL 2,502,506

GUN SIGHT Original Filed March 27, 1945 6 Sheets$heet 6 lnz/enzo rs T159 rmeszzchase WZZZZc zm VGood/zue Ernesz Give/ 65 Patented Apr. 4, 1950UNITED STATES PATENT OFFICE GUN SIGHT Original application March 27,1945, Serial No. 585,150. Divided and this application July 19, 1946,Serial No. 684,864

1 Claim.

This invention relates to ordnance and is illustrated as embodied in animproved sight for use, for example, in, an armed turret disclosed inapplication for United States Letters Patent Serial No. 585,150, filedMarch 27, 1945, in the name of Ernest E. Chase et al., now Patent2,450,541, granted October 5, 1948, the present application being adivision of the above identified application.

It is an object of the present invention to provide an improved sightfor use in said armed turret.

Various features of the invention will be understood and appreciatedfrom the following detailed description read in connection with theaccompanying drawings, in which Fig. 1 is a side view, partly inlongitudinal vertical section, of the interior of an illustrative armedturret and of a gun and various mechanisms which are incorporated in andform part of said turret;

Fig. 2 is a diagrammatic view, showing various connections between thegun, a lead setting box, and sights of the turret;

Fig. 3 is a perspective view of a sight used by an azimuth tracker inthe turret;

Fig. 4 is a section on line IV-IV of Fig. 3;

Fig. 5 shows the sight, partly in side elevation and partly in sectionon line V-V of Fig. 3;

Fig. 6 is a section on line VIVI of Fig. 5;

Fig. '7 is a view showing, partly in section and .partly in sideelevation with covers removed,

portions of a turret, commanders sight and a lead setting box by the useof which the commander throws leads into the various sights;

Fig. 8 is a section on line VIII-VIII of Fig. 7;

Fig. 9 is a plan view of the lead setting box; and

Fig. 10 is a diagram used in connection with the description of azimuthand elevation lead setting mechanism.

The illustrative armed turret 38 which is disclosed in detail in saidapplication Serial No. 585,150 comprises a Bofors 40 mm. gun 40 (Fig. 1)rate controlled electrically operated means for rotating the turret,together with the gun, in azimuth and the gun in elevation with relationto the turret, and manually operated mechanism for actuating said means,portions of said mechanism being operated by a turret commander forinitially training the gun on a target. After the gun 40 has beentrained on the target, the commander renders his rate control actuatingmechanism inoperative, the training of the gun thereafter being turnedover to azimuth and elevation trackers who are seated on stools 42, 44

2 (Fig. 1), respectively, and drive the turret, through mechanicalconnections, said connections at such time being adapted to actuate saidrate controlled electrically operated means.

The commander, standing upon a platform 46 (Fig. 1) and observing orspotting the target through an open sight 48 (Figs. 1 and 2) mountedupon a cupola 50 of the turret 38, initially trains the gun 40 on thetarget by the use of a grip 52 (Fig. 1) forming part of rate controlmechanism, a hatch cover 54 (Fig. 1) of the cupola at that time beingopen. The commander then moves to a seated position upon a stool 56,which is positioned above the platform 46, and shuts the hatch cover 54,the target thereafter being observed by him through an elbow telescope58 (Figs. 1 and 2) as he trains the gun 49 on the target. While the gun40 is being initially trained on the targettheazimnthf-andelevationtrackers observe saidtaijgct...through-elbow..telescopes 60 '(Fi'gs. "1:2; 3 and 5), 62(Figs. 1 and 2), respectively, extending outside the turret 38 andforming parts of sights hereinafter described.

When the commander has trained the gun 40 on the target he releasessolenoid control buttons 64 (Fig. 1) located on the grip 52, therebytransferring control of the electrically operated means to the azimuthand elevation trackers who turn wheels. 66, 68 (Fi g. 1), respectively,to retain, through mechanism portions of which will be-described later,horizontal and vertical hairlines (not shown) of the elbow telescopes60, 62, respectively, and accordingly the gun 40, on the target. Thecommander now being free to observe the fire on the target, throws leadsinto the elbow telescopes 58, 60 and 62 by turning azimuth and elevationwheels ID, 12 (Figs. 1, 2, 8 and 9) of a lead setting box 14 inaccordance with the observed trajectory of tracer bullets fired at thetarget, thereby causing the trackers to shift the fire to the target, ifnecessary, and thereafter to maintain said fire upon the target as itchanges its speed and/or direction.

There is provided in a front wall of the turret 38 an arcuate openingI22 (Fig. 1) sufiiciently large to permit elevation of the gun throughranges varying from minus 15 to from the horizontal and a small openingI24 in the lower front portion of the turret for the reception of achute I26 for disposing of empty cartridge cases. There are alsoprovided at the right side of the turret 38 three openings I28 forreceiving sights I30 formed in part by the elbow telescopes 58, 60, 62.

A pair of trunnions [32 (Figs. 1 and 2) secured to a breech casing orreceiver I34 of the gun 48 are mounted for rotation in horizontal boresof trunnion blocks I36 (Fig. 1) bolted to trunnion block supports I38,which are bolted or otherwise rigidly secured to a floor of the turretand are connected together by a transverse cylindrical web (not shown).Accordingly, the gun rotates with the turret for training in azimuth andis rotated about a common axis I44 (Fig. 2) of the trunnions I32 withrelation to the turret for training the gun in elevation. In order toswing the gun in elevation, there is secured to the breech casing I34 ofthe gun a segment gear I46 (Figs. 1 and 2) driven by a gear I48 which isrotatable, in response to movement of the rate control mechanismactuated by the commander's grip 52 or in response to movement of theelevation trackers wheels 68 and the rate control mechanism actuated bysaid wheels.

Sight drives from gun elevating mechanism In order automatically to varythe elevation of the three elbow telescopes 58, 68, 62 and the opensight 48 in accordance with changes in the elevation of the gun 48, agun elevating shaft I24 (Fig. 2) to which the gear I48 is pinned hassecured to its right end a bevel gear 8) which is enclosed in a housing(not shown) secured to one of the trunnion block supports I38 and mesheswith a bevel gear 8I4 secured to the upper end of a vertical drivingconnection (H6. The lower end of the driving connection 8; has securedto it a bevel gear 8I8 which is rotatably mounted in a housing (notshown) secured to one of the trunnion block supports I38 and drives abevel gear 822 secured to a horizontal shaft 824 mounted for rotation insaid housing. The shaft 824 is operatively connected through a drive 825(Figs. 1 and 2) extending along the floor and the right side wall of theturret to a bevel gear 826 secured to the lower end of an input shaft828 extending upward into the lead setting box I4. As will be explainedlater, changes in the elevation of the gun 48 and in the elevationdeflection angle between the elbow telescopes 58, 68, 62 and the gun areadded algebraically in a differential 838 (Fig. 7) which is operativelyconnected to the shaft 828 and which, through mechanism hereinafterdescribed, drives an elevation output shaft 832 of the lead setting boxI4. The connections between the elevation output shaft 832 of the leadsetting box I4 and the elbow telescopes 58, 68, 62 will be describedlater.

Sights As above stated, the elbow telescopes 58, 66, 62 may be angularlyadjusted in azimuth and in elevation with relation to the gun to varythe azimuth and elevation deflection angles between the gun and thesights, through mechanism which will be described presently and isoperated by the commander as he observes the efiect of fire upon thetarget. The sight mechanism through which the elbow telescopes 58, 68,62 are angularly adjusted in elevation and in azimuth with relation tothe gun is identical.

Each of the sights I38 comprises an elbow telescope 58, 68 or 62 havinga pair of ribs 848 (Figs. 3, 5 and 6) and mounted upon the ribs is anadapter sleeve 842 (Fig. 5) which is rotatable in a cylindrical bore 844of a block 846 comprising two parts secured together by screws 841(Figs. 5 and '7). The adapter sleeve 842 has a portion 848 (Fig. 6) ofreduced diameter provided with a pair of slots 858 in which fitextensions I (Figs. 5 and 6) of one of the ribs 840 of the telescope.The block 846 has formed integral with it an upper trunnion 852 (Figs.3, 4 and 5) and secured to it by screws 854 (Fig. 5) is a lower trunnion856 (Figs. 3, 5 and 7), said trunnions being swiveled for rotation abouta common axis 858 in bores 868, 862 of a housing 864. The housing 664 ofthe sight I38 is rotatably mounted upon a hanger pin 866 (Figs. 3 and 5)supported by a bracket 868 secured by screws 818 to the wall of theturret 38. The sides 812 (Fig. 3) and a gear box 884 of the housing 864are formed integral and are secured by screws 816 (Figs. 3 and 4) to thetop of the housing, the housing being secured in its vertical positionupon the hanger pin 866 by nuts 818 (Figs. 3, 5 and 7) threaded onto ascrew 889 which passes through an enlarged recess 882 (Fig. 5) of thehousing and is secured to the turret wall. In order to insure that theaxis 858 of the trunnions 852, 856 shall be exactly vertical, a spiritlevel 884 (Fig. 3) is secured to the housing 864. The inner verticalfaces 886 (Fig. 4) of the housing 864 are cylindrical and are centeredabout the axis 858 of the trunnions 852, 856, the curved lateral sides888 of the block 848 being complemental to and just clearing the faces886 of the housing.

Mounted in a recess 898 (Fig. 5) of the block 846 is a bevel gear 892(Figs. 3, 5, 6 and '7) which is secured to a flange of the adaptersleeve 842 by screws 894 (Figs. 3, 5 and 6), a two-part plate 896 beingforced by screws 898 against the inside faces of the block and the innerrib 848 of the elbow telescope 58, thereby insuring against movement ofsaid telescope lengthwise of its axis 988 (Figs. 3 and 5) with relationto the block 846. Secured by screws 982 (Fig. 5) to the adapter sleeve842 is a hood 984 which affords protection for the portion of thetelescope 58 extending outside of the turret. Since the elbow telescopes58, 68 and 62 are of the standard type now in use it will not benecessary to describe said telescopes in detail.

In order to swing the block 846 into different angularly adjustedpositions about the axis 858 of its trunnions 852, 856 to vary theazimuth deflection angle between the gun 48 and the elbow telescope 68,the trunnion 856 has keyed to it an azimuth worm gear 986 (Figs. 3, 5and '7) which meshes with an azimuth worm 988 pinned to a shaft 8 I 8which, as will appear later, is operatively connected to an azimuthoutput shaft 9I2 (Figs. 1, 2, 7, 8 and 9) of the lead setting box I4,which, as above explained, is controlled by the commander.

To rotate the elbow telescope 68 in the block 846 about its horizontalaxis 988 the bevel gear 892, which is secured to the adapter sleeve 842,meshes with a bevel gear 9M (Figs. 3, 5 and. '7) which is arranged in arecess of the block and is fixed to the upper end of a shaft 9l8 fittingin a concentric or coaxial vertical bore of the trun nion 856. Securedto the lower end of the shaft 9I8 is an elevation gear 928 (Figs. 3 and5) meshing with an elevation worm 922 rotated by and also movablelengthwise along a shaft or rotatable drive member 824 rotatably mountedin the gear box 814 of the housing 864.

It will be apparent that rotation of the elbow telescope 58 about theaxis 858 of the trunnions 852, 856 will, unless compensated for, causethe bevel gear 892 to turn about the horizontal axis 988 and introducean elevation error into the sight. In order to insure against thisoccurring, the worm 922 during movement of the block 846 about the axis858 of the trunnions 852, 856 is moved relatively to the shaft 924 by ayoke 926 secured by screws 928 to a rack 930 which is slidablelengthwise in bores 932 (Fig. 7) of the gear housing 814 and meshes witha compensating gear 934 (Figs. 3 and 5) secured to the trunnion 856 andhaving the same pitch diameter as the gear 929. With such a constructionit will be apparent that when the block 846 is swung about the verticalaxis 858 of the trunnions to vary the azimuth lead. the worm 922 slidesalong its shaft 924 the proper amount to insure against the gear 892being rotated with relation to the block about its axis 988.

As above explained, the proper lead corrections are made in the leadsetting box 14, which is operated by the commander in accordance withhis observation of tracer bullets fired upon the target.

Lead setting box Since the gun 48 moves in azimuth, together with theturret 38, it is only necessary to swing the elbow telescopes 58, 68, 62about the axis 858 (Figs. 3 and 5) of their trunnions 852, 856 in orderto give the gun the proper lead in azimuth. It will be apparent,however, that since the gun is moved in elevation with relation to theturret it is necessary to have each of the elbow telescopes swing aboutits horizontal axis 908 to the same degree that the gun swings about theaxis I44 (Fig. 2) of its trunnions I92 and to add to such movement thedesired lead in elevation. As above stated, the elevation deflectionangle may be varied by the commander by rotating the hand wheel 12 whichis fixed to the outer end of a shaft 936 (Figs. '1 and 8) journaled in abearing of the lead setting box 14. Pinned to the inner end of the shaft936 is a bevel gear 938 meshing with a bevel gear 948 secured to anupstanding shaft 942 to which is pinned a worm 944 meshing with a gear946 keyed to an index shaft 948. Pinned to the rear end of the shaft 948is a large gear 959 in driving relation with a smaller gear 952' (Fig.'7) secured to a lower horizontal shaft 954 rotatably mounted in thelead setting box. Rotation of the shaft 954 is transmitted through bevelgears 956 to an input shaft 958 of the above-mentioned differential 838(Fig. '1). As above stated, changes in elevation of the gun areintroduced into the differential 898 by the elevation input shaft 828(Figs. 1, 2 and '7) which is movable in response to movement of thesegment gear I46 (Figs. 1 and 2) of the gun 48. The elevation componentsfrom the lead setting box and the gun elevation input shafts 958, 828are added aglebrai'cally in the differential 838, which comprises a cage968 (Fig. '7) to which is secured a gear 962 (Figs. 7 and 8) meshingwith a gear 964 fixed to the elevation output shaft 832 which isoperatively connected through driving connections 966 (Figs. 1, 2 and'7) to the elevation shafts 924 (Figs. 2, 3, 5 and 7) of the commandersand trackers sights.

In order to register the elevation deflection angles, there are providedindex and Vernier dials 968, 918 (Figs. 8 and 9) which are calibrated inmils and are viewed through a window 91I (Fig. 9) in the top of the leadsetting box 14. The dials 968, 918, respectively, are freely mountedupon and pinned to the shaft 948, the index dial 968 being rotated atone-ninth the speed of the Vernier dial 918 by means ofa gear train com-6 prising a gear 912 (Figs. 7 and 8) pinned to the shaft 948, a pair ofidler gears 914 mounted upon a fulcrum pin 916 fixed to the lead settingbox 14, and a gear 918 freely rotatable upon the shaft 989 and pinned tothe index dial 968. In the illustrative construction the maximum lead ofthe gun in elevation is approximately 450 mils, or about 25, the indexdial at such time having been rotated slightly less than one-half of arevolution to the right or to the left from its neutral position, shownin Fig. 9, in which position the zero marks on the dials register withmarks 988 on the lead setting box 14.

The azimuth lead of the gun is varied by the rotation of the hand wheel18 which is pinned to the outer end of a shaft 982 (Figs. '1 and 8)journaled in the lead setting box 14. Secured to the inner end of theshaft 982 is a bevel gear 984 meshing with a bevel gear 986 pinned to avertical shaft 988 which carries a worm 998 in driving relation with agear 992 secured to an index shaft 994. Pinned for rotation with theshaft 994 is a vernier dial 996. The inner end of the shaft 994 hassecured to it a gear 998 (Fig. 8) driving a compound gear I888operatively connected to a gear i882 which is fixed to the azimuth leadoutput shaft 9I2 (Figs. 1, 2 and 7). The shaft 9I2 through upwardlyextending driving connections I884 (Figs. 1, 2 and 7) operates the shaft9) (Figs. 3, 5 and 7) of the commanders sight I38 and through drivingconnections I899 (Figs. 1 and 2) extending downward and along the rightwall of the turret operates the shafts Bio of the trackers sights I38.

Freely mounted upon the shaft 994 (Figs. 7 and 8) is an index dial I888(Figs. 8 and 9), and secured to the shaft is a pinion I8I8 which mesheswith a compound gear I8I2 which is rotatably mounted upon a fulcrum pinI 8 I4 secured to the lead setting box 14 and which meshes with a gearI8I6 rotatably mounted upon the shaft 994 and pinned to the index dialI888, the arrangement being such that the index dial partakes ofone-ninth 0f the rotation of the shaft 994 and accordingly the Vernierdial 996. In the lead setting box 14 is a window I8I8 (Fig. 9) throughwhich the commander may observe the amount of lead in azimuth. Thecalibration of the azimuth Vernier and index dials 996, I888 is similarto that of the elevation Vernier and index dials 919, 968. As in theelevation lead setting mechanism, the maximum lead in azimuth is 450mils, or approximately 25.

The course of a target ma be divided into two components, one tangentialand the other radial to the line of sight. In tracking the target thetangential component is considered in computing the azimuth lead and theradial component is considered in computing the elevation lead.

When the tangential component is clockwise, as viewed from above (Fig.10) the azimuth lead, that is, the lead of the gun in relation to theline of sight as viewed from above, is also clockwise. It will beapparent that the tangential component remains in the same direction solong as the target remains on the same general course, such, forexample, as from A to B. Should the target reverse its course, theazimuth lead would be counterclockwise.

It will be noted, however, that the radial component changes from aninward or incoming direction, shown at A, Fig. 10, to an outward oroutgoing direction, as shown at B, during travel of the target in itscourse from A to B. Accordingly, while following the target throughcourse A to B, the elevation lead will have to be changed from an inwardto an outward one. The inward elevation lead may be said to require anupward vertical deflection of the gun from its line of Sight and theoutward lead may be said to require a downward vertical deflection ofthe gun from th line of sight. It is evident that the elevation leadwill be maximum at the extreme ranges A or B and will be a minimum atthe minimum range C, the elevation lead changin in direction at thispoint. The course A to B may be referred to as a clockwise course, theportion of the course to the left of the minimum range point C beingconsidered the incoming part of the course and that portion of thecourse to the right, the outgoing part of the course. It will beunderstood that for a clockwise direction course the gun will have anupward vertical deflection for the incoming part of the course and adownward vertical deflection for the outgoing part of the course. Thiswill also hold true for a course where no tangential component ispresent.

Whenthereis noleadinazimlltn the zeros on the index and Vernier dialsI008, 996 of the azimuth lead setting mechanism are in alinement withmarks IOI9 (Fig. 9) on the lead setting box 14, and when there is nolead in elevation the zeros on the vernier and index dials 968, 910 ofthe elevation lead setting mechanism are in alinement with the marks 980of the lead setting box. 0

When the commander rotates the azimuth wheel 10 clockwise, as viewedfrom the front of the lead setting box I4, there is provided a clockwiselead in azimuth, the azimuth index and Vernier dials I008, 996 moving inthe direction of the arrow I02I, the dial numbers which increaseprogressively to the left from zero and are colored blue then beingread. When the commander rotates the azimuth wheel I0 in acounterclockwise direction from its neutral position, a counterclockwiselead in azimuth is provided, the dials I008, 996 moving in a directionopposite to the direction of the arrow I02I and dial numbers whichincrease progressively from the right of zero and are colored whitebeing read.

When the elevation wheel I2 is rotated clockwise, as viewed from thefront of the lead set-, ting box 14, from a neutral position in whichthere is no lead in elevation and in which the zeros on the index andVernier dials 968, 910 are in registration with the marks 980 on thelead setting box I4, the gun will be given an outgoing lead inelevation, the dials moving in the direction of the arrow I023 and thecommander reading blue dial numbers which increase progressively to theleft from zero, as viewed in Fig. 9. When the elevation wheel 12 isturned counterclockwise, the gun will be given an incoming lead, thedials 968, 910 moving in a direction opposite to the direction of thearrow I023 and white dials numbers which increase progressively to theright from zero being read.

In order to insure against breakage of the lead setting mechanism abovedescribed due to applying too much force to the wheels 10, 12, there'are provided stops I028 (Figs. 7 and 8) which, when the index dials 968,I008 operatively connected to the elevation and azimuth lead settingmechanism have been rotated just less than one-half of a revolution andaccordingly register approximately 450 mils, are engaged by abutmentsI022, best shown in Fig. 7, formed upon collars I024 secured to theshafts 936, 982. The mechanism for operating said stops I020 comprisescams I026 (Fig. 7) carried by the index dials 968, I008, re-

spectively. Secured to the inner ends of shafts I028 which are journaledin the lead setting box 14 and to which the stops I020 are pinned arelevers I030. Just before the index dials 968, I008 have reached thelimits of their movement, the levers I 030 are engaged by the cams I026,causing the stops I020 to be raised into positions to be engaged by theabutments I022 on the collars I024, thus preventing the shafts 936, 982from being turned any farther by the commander. During the normaloperation of the lead setting device, the stops I020 are held in theirdepressed positions, shown in Fig. 7, against screws I08I out of thepath of movement of the abutments I022 by springs I032 which operateagainst the levers I030.

In order that the commander while viewing the target may have a, fairidea of the magnitude of the leads in azimuth and elevation, there areprovided clicker devices comprising recessed disks I034 (Figs. 7 and 8)which are secured to the forward ends of the index shafts 948, 994 andare engaged by leaf springs I036 secured by screws I038 to the leadsetting box 14. For every 25 mils of rotation of each of the indexshafts 948, 994 one of the springs I036 falls into a depression I040 ofthe associated disk I034, causing an audible click.

Having described our invention, what we claim as new and desire tosecure by Letters Patent of the United States is:

In a gun sight, a block having trunnions mounted for rotation about anaxis, an elbow telescope mounted for rotation in the block about asecond axis arranged at right angles to the firstnamed axis, a shaftrotatable in one of the trunnions in coaxial relation with thefirst-named axis, intermeshing bevel gears secured to said shaft and tothe elbow telescope respectively, an azimuth worm gear fixed to one ofsaid trunnions, flgzlmljh worm meshing with the azimuth worm gear, meansfor operating the azimuth worm to move the blocl; together with theelbowtelescdiYe aboiit'said'first-na'ind "axis, an leya on worm gear securedto the shaft, a rotatable drive member, an elevation worm which ismounted for rotation with said drive member and is slidable on saidmember, a compensating gear which has the same pitch diameter as theelevation Worm gear and is secured to the trunnion, a rack meshing withthe compensating gear and constructed and arranged to slide theelevation worm on the rotatable drive member in response to rotation ofthe compensating gear to rotate the elevation worm gear and accordinglythe bevel gear secured to the shaft a sufficient number of degrees toinsure that rotation of the elbow telescope in azimuth shall not effectrotation of the elbow telescope in elevation.

ERNEST E. CHASE. ERNEST S. NOKES. FRANK E. STRATTON. WILLIAM V. GOODHUE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 433,020 McKellen July 29, 18901,233,929 Strate July 17, 1917 1,412,758 Sperry et a1. Apr. 11, 19222,372,613 Svoboda 1. Mar. 27, 1945 2,385,348 Chafee Sept. 25, 19452,407,665 Holschuh Sept. 17, 1946

